lock() COHERENT System Call lock() Prevent process from swapping lock(flag) int flag; The COHERENT system can swap a process in and out of memory. However, real-time response sometimes requires that a process be locked in memory. When called with a nonzero flag, lock prevents the calling process from swapping (unless swapping is required to increase its memory size). Calling lock with a flag of zero unlocks the process. This call is restricted to the superuser. Processes doing raw I/O are automatically locked into memory for the duration of the I/O operation. ***** See Also ***** COHERENT system calls, ps, swap ***** Diagnostics ***** lock returns zero if it performs the indicated action and -1 otherwise. An error occurs if the caller is not the superuser. ***** Notes ***** The existence of several locked processes may cause memory frag- mentation. Therefore, all locked processes should be created just after the system is booted, if possible. In general, lock should be avoided if any alternative exists. COHERENT Lexicon Page 1